1. Field of the Invention
This invention relates generally to the field of computer generated video displays, and relates more particularly to the generation of a color display on a terminal or personal computer while using the existing computer software designed for a monochrome display.
2. Description of the Prior Art
A data terminal or personal computer coupled to a host processor may include a monochrome cathode ray tube for displaying text. Individual characters, words, lines or areas of the displayed text may be highlighted in several ways through the use of attribute characters. Attribute characters may be used to have certain characters or words displayed with special visual attributes such as low intensity. Therefore, an attribute character with a low intensity bit is read out of a video random access memory (RAM) on the same access that the text character is read out of the RAM.
Similarly, other attribute bits are used to underline characters or words, show the characters or words in inverse video, have certain characters or words blink or have certain characters or words not be displayed. If the host computer is coupled to a data terminal or personal computer having a color CRT display, it is desirable to display the attribute features as well as the text in selected colors. Since the host computer is programmed to display in the monochrome mode, the host computer must be reprogrammed to display color. Also, the host computer processes many applications programs, converting each monochrome applications program to display in color is time consuming and therefore expensive.
The selection of color for text, status and error information was previously designed into a Honeywell PC 7800 Emulator.